<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>

</head>
<body>
    <form>
        宽度：
        <input id="width" type="text"></input>
        <br>
        长度：
        <input id="height" type="text"></input>
        <br>
        <input id="calculate" type="submit" value="计算"></input>
        <!-- <input id="calculate" type="button" value="计算"></input> -->
        <br>
        周长：
        <!-- disabled:input标签可读不可编辑 -->
        <input id="perimeter" type="text" disabled></input>
        <br>
        面积：
        <input id="area" type="text" disabled></input>
        <br>
    </form>
    
</body>
<script type="text/javascript" src="js/cal.js"></script>
</html>